The sperm whale is a large toothed whale. A marine mammal, it possesses the largest brain of any animal. A mature male can grow to 67 ft long, its head representing up to one-third of the animal's length. The largest living toothed animal, the species feeds primarily on giant and colossal squid. It is the deepest diving mammal. Living up to 70 years, a mature sperm whale has few natural predators.